Fluid actuated vane type motor



Aug. 9, 1955 P. E. SCHMID FLUID ACTUATED VANE TYPE MOTOR 2 Sheets-Sheet 1 Filed July 26, 1951 Fcw/ E. Sch/77m INVENTOR.

A TTO/TNEY 9, 1955 P. E. SCHMID FLUID ACTUATED VANE TYPE MOTOR 2 Sheets-Sheet 2 Filed July 26, 1951 ATTORNEY United States Patent fiiic 2,7 14,3 76 Patented Aug. 9, 1955 2,714,876 FLUID ACTUATED VANE TYPE MOTOR Paul E. Schmid, Houston, Tex., assignor to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Application July 26, 1951, Serial No. 238,664 2 Claims. (Cl. 1 21-87) This invention relates broadly to portable fluid actuated rotary motors, but more particularly to vane type motors.

Motors having eccentrically walled chambers are well known in this art, wherein the most common design consists of a cylindrical chamber having a rotor mounted :30

eccentrically therein in line contact with the chambers wall and carrying radially movable vanes. Motive fluid is admitted to and exhausted from the vanes through ports located on the opposite sides of the line contact. In this type of motor, motive fluid is permitted to expand and effectively act on the vanes for a relatively short distance before it is caused to exhaust. The power are of such tools, that is, the distance during which the motive fluid is capable of work producing expansion by acting on the vanes is generally less than half a revolution of the rotor.

From this most common type, changes have been made, especially in the shape of the rotor chamber, with a view to producing more efficient designs, but none have been produced to utilize the motive fluid to maximum expansion.

It is therefore one object of this invention to produce .an improved fluid actuated rotary motor of the vane carrying rotor type, with a rotor chamber shaped to utilize the motive fluid to maximum expansion.

Another object of this invention is to produce such a motor wherein the rotor chamber is made to start at the inlet port and to grow gradually deeper until it reaches the exhaust port, thereby enabling expansion of the motive fluid to continue as it acts on the vaned rotor from the inlet to the outlet ends of the chamber.

Other objects will be in part obvious and in part pointed out hereafter.

. In the accompanying drawings:

Figure 1 is a longitudinal sectional view of a simplified fluid actuated motor embodying the invention.

Figure 2 is a cross sectional view taken on line 2-2 in Figure 1.

Figure 3 is a diagrammatic sketch, corresponding substantially to Figure 2, illustrating the shape of the rotor chamber, and the method used in obtaining it.

Referring to the drawings, designates a stator closed by end plates 11 and 12, which are clamped against its ends by caps 13 and 14 through which extend four clamping bolts 15. The interior of the stator 10 forms a rotor chamber 16 extending the full length thereof, in which is rotatably mounted a rotor 17. The main body of the rotor fits closely between the end plates 11 and 12, and has one reduced end portion 18 extending centrally through the plate 11 and a similar end portion 19 extending through plate 12. Adjacent each end portion 18 and 19, the rotor is journalled in ball bearings 20 and 21, mounted in the caps 13 and 14 respectively. From the bearing 20, the rotor extends through the cap 13 to form the driving end 22 of the motor, to which may be secured a work performing tool such as grinding wheel, drill chuck or the like. In the cap 14, there is provided a screw threaded bore 23 in which is screwed one end of a motive fluid conveying conduit 24. From the bore 23, motive fluid is admitted into three inlet ports 25 provided in the wall of the cylinder 10 and opening in the rotor chamber 16 through three longitudinally spaced moon-shaped grooves 26. Also provided through the wall of the stator 10 and opening in the rotor chamber 16, there is an exhaust passage 27.

As is customary in motors of this type, the main body of the rotor between the end plates 11 and 12 is provided with a plurality of laterally extending slots 28 having substantially rectangular vanes 29 slidable therein. During operation of the motor, the vanes are urged outwardly in contact with the Wall of the chamber 16 by pressure fluid admitted under them through small ports 30.

Referring now more particularly to the invention, the rotor 17 is eccentrically mounted in the chamber 16 in a manner causing it to always contact. a relatively small portion of area 31 of the wall thereof. As shown in Figure 3, this contact area 31 is limited to an arc of 25, and extends 12 on one and 13 on the other side of a plane A--A coincident with the axes of the stator 10 and rotor 17. The curvature of this contact area corresponds exactly to that of the rotor, and the existing contact is calculated to enable free rotation of the rotor while preventing motive fluid from escaping at that point between the rotor and the wall of chamber 16.

Formed in the rotor chamber 16 between the rotor and the wall of the chamber, there is an inlet portion 32 which starts at the right end, in Figure 2, of the contact area 31 and extends partly around the rotor up to the start 33 of the exhaust passage 27. In Figure 3, this inlet portion is shown to extend 280 around the t rotor 17. Similarly formed in the chamber 16, there is an outlet portion 34, which commences at the starting point 33 of the exhaust passage 27 and has its end coinciding with the left end, in Figure 2, of the contact area 31. In Figure 3, this outlet portion is shown to extend 55 from the start 33 of the exhaust passage 27.

In the inlet portion 32, the wall of the rotor chamber 16 is substantially spiral-shaped, or referring to the depth of this portion, it gradually and uniformly increases within its entire are of 280. At 33, that is, where the open ends of portions 32 and 34 are merged, the maximum depth of the two portions is equal. There after the depth of the outlet chamber 34 is sharply reduced until the rotor chambers wall coincides with the left end of the contact area 31.

As clearly shown in Figure 2, the inlet moon-shaped grooves 26 open in the inlet portion 32 near the beginning thereof, and the exhaust passage 27 opens in the outlet portion 34 substantially the full extent thereof.

The curve of the inlet portion 32 may be obtained by adding to the rotor diameter a unit dimension at equally peripherally spaced points. For instance, in Figure 3, the points are shown to be spaced 20". In other words, the unit dimension is added to the rotor diameter every 20 until the 280 mark is reached, thereby producing an inlet chamber of a gradually and uniformly increasing depth. It will of course be understood that the unit dimension is equal to the maximum depth B of the chamber at the 280 mark, divided by the number of equally spaced points used to trace the curve. For instance, since in Figure 3 the 280 curve has been traced by fourteen points spaced 20 apart, it will be clear that the unit dimension is equal to the maximum depth B divided by fourteen. A

The outlet or exhaust portion of the chamber extending within the 55 arc may be obtained similarly by adding to the diameter of the rotor in a counterclockwise direction, a unit dimension at equally spaced points,

3 the unit dimension being equal to the maximum depth B divided by the number of points. For instance, in Figure 3 the 55 curve has been traced by five points spaced 11 apart, thereby making the unit dimension equal to .B divided by five.

In the. operation of the motor, motive fluid such as compressed air. supplied through the conduit 24 is admitted. into the rotor chamber 16 via the inlet ports 25 and grooves 26. From the rotor chamber, some motive fluid will flow to the bottom of the rotor slots 28 to urge the vanes 29 into engagement with the wall of the chamber, causing motive fluid to act on the vanes for imparting rotation to the rotor.

A clearly'shown in Figure 2, it is evident that any two;adjacent vanes form, with the rotor and the wall of chamber 16, a pocket of varying volumetric capacity. Thezcapacityof any one pocket is smallest when it is opened to the grooves 26, that is when it is supplied with motive fluid under relatively high pressure. Thereafter, its depth and consequently its volumetric capacity gradually increases, enabling the motive fluid trapped in the pocket to expand and act on a gradually increasing exposed .area of the vanes. Since eachpocket, While located in the inlet portion 32, has its front end relative to the direction of rotation of the rotor larger than its rear end, itwill be understood that there exists an effective differential vane area subjected to the action of the expanding motive fluid for imparting rotary power to the rotor.

As the forward vane of each pocket reaches the exhaust passage 27, the expanded motive fluid in the pocket and under the vane is free to exhaust therefrom and enables inward movement of the vanes. The inward movement is effected by the contact of the vanes with the wall of the outlet portion of the chamber 16, which wall is rapidly approaching the rotor 17 and joins with the contact area 31. At this point the blades are flush with the peripheral wall of the rotor and free to pass the contact area 31 preparatory to starting the next cycle.

From the foregoing description, it will be understood that the subject invention provides a vane type motor with a rotor chamber enabling motive fluid to remain effective during an arc of at least 280, during which the effective vane area is gradually and uniformly increased, thereby utilizing the motive fluid to greater expansion than that used in conventional motors of this type, and resulting in a vane type motor of higher efliciency than heretofore obtained.

It will also be understood that by reversing the inlet and outlet ports and imparting, from a source of auxiliary power such as electric motor, rotation to the rotor in counterclockwise direction, the subject construction could be utilized as an efiicient fluid pump.

I claim:

1. In a fluid actuated rotary motor. a stator formed with a rotor chamber, a rotor of circular cross-section eccentrically mounted in said chamber, vanes slidably carried by said rotor in end contact with the wall of said chamber, a contact area between said rotor and wall, motive fluid conveying inlet and outlet passages opening into said chamber, one on each side of said contact area, an inlet portion in said chamber peripherally extending substantially 280 from said inlet passage which opens thereinto to the opening of said outlet passage, an outlet portion in said chamber of a peripheral length equal to that of the opening of said'outlet passage and with a concave wall adapted to be contacted by said vanes in substantially perpendicular relationship therewith to efiect their inner movement relative to said rotor, the depth of said inlet portion relative to said rotor gradually and uniformly increasing throughout its length, thereby causing said vanes to expose a gradually and uniformly increasing effective area as to the motive fluid during their travel from one to the otherxend of said inlet portion.

2. In a fluid actuated rotary motor, a stator formed with a rotor chamber, a rotor of circular cross-section eccentrically mounted in said chamber, vanes slidably carried by said rotor in end contact with the'wall of said chamber, a contact area between said rotor and wall, motive fluid conveying inlet and outlet passages opening into said chamber, one on each side of said contact area, the length of the opening of said outlet passage peripherally within-said chamber being greater than that of the opening of said inlet passage, an inlet portion in said chamber peripherally extending from said inlet passage which opens thereinto to the opening of said outlet passage, an outlet portion in said chamber of a peripheral length equal to that of the opening of said outlet passage and with a concaved wall adapted to be contacted by said vanes in substantially, perpendicular relationship therewith to effect their inner movement relative to said rotor, the depth of said inlet and outlet portions relative to said rotor being such as to enable a relatively slow and uniform outward movement of said vanes during their travel throughout said inlet portion and a fast but uniform inward movement during their travel throughout said outlet portion.

References Cited in the file of this patent UNITED STATES PATENTS 268,522 Muller Dec. 5, 1882 867,172 Troup et al. Sept. 24, 1907 878,998 Penington "Feb. 11, 1908 994,400 Holt June 6, 1911 1,972,744 Lister Sept. 4, 1934 2,057,381 Kenney'et al. Oct. 13, 1936 

